The subject invention relates to static punched card readers, and specifically to optical punched card and badge readers. These devices are typically used as programming devices for holding fixed instructions or data such as parameter values, and are particularly useful in data acquisition systems such as security systems, hospitals, parking lots, time clocks, data collection and process control.
As is well known, optical card readers transform the punched holes in the data cards into electrical impulses by means of photoelectric cells which are activated as the punched card passes over a light source. The generated signals are then carried by well known circuitry to a read out terminal or device. Known optical card readers have several shortcomings, however. Some known readers have a sensor for each column and row of the data card. As a result, external means of scanning the data field is required. Discrimination of responses occurs subsequently. Other card readers have sensors for each row of the data card. When the card is inserted into the reader it is transported by a drive mechanism. This provides a time base which enables discrimination of responses along the rows and columns. Another similar type of reader includes sensors along the columns of the data card. However, insertion of the card is performed manually, and discrimination of responses obtained by external electronic scanning.
In addition, many of the known readers are not completely reliable and do not provide full validity checks. Further, they are often complex in structure resulting in greater chance of breakdown as well as higher manufacturing costs.
Accordingly, it is an object of the subject invention to provide an optical punched card reader that does not require external scanning or discrimination means.
It is another object of the subject invention to provide an optical punched card reader that is completely reliable and provides full validity checks.
It is further object of the subject invention to provide an optical punched card reader having the above characteristics which is simple in construction and economical to manufacture.